1. Field of the Invention
The present invention relates to an improvement in a CRT display control system and, more particularly, to a character display control system in a CRT display system.
2. Description of the Prior Art
There are two types of conventional display control systems which control display of characters of plural rows in a CRT display system. In one conventional type, a dot matrix size assigned to one character, and a line spacing width are fixed. That is, both of the display allowed raster section and the display inhibited raster section are fixed in accordance with the dot matrix size assigned to one character. In this case, the dot matrix size can not be changed without modifying the circuit construction. In another conventional type, the entire row height (including the line spacing) is formed as the display allowed raster section. A character generator ROM stores combined pattern data each of which includes a character pattern data and a line spacing data. Therefore, the character generator ROM must have a considerably large memory capacity because the caracter generator ROM must store the line spacing pattern data in addition to the character pattern data.